Rapid assessment of surface-water flood-management options in urban catchments

Abstract

Surface-water flooding in urban areas has become a pressing issue due to changing precipitation patterns, expanding urban areas and ageing drainage infrastructure. Selection of flood-management options for widespread implementation using quantitative performance measures is both technically and computationally demanding, which limits the evidence available for decision support. This study presents a new framework for surface-water flood-intervention assessment at high resolution. The framework improves computational efficiency through utilisation of accessible data, simplified representations of interventions and a resource efficient cellular automata flood model. The advantages of this framework are demonstrated through an example case study where the performance of 12 high-level intervention strategies has been evaluated. Results from the case study demonstrate that the framework is able to provide quantitative performance values for a range of interventions. The speed of analysis supports the application of the framework as a decision-making tool for urban water planning.

Comparing cost‐effectiveness of surface water flood management interventions in a UK catchment

“…The surface water intervention assessment framework presented in Webber et al (, b, c) is a four‐stage process that includes: characterising the study area, representing interventions, simulating scenarios, and analysing intervention performance. Flood simulation is undertaken using the CADDIES model.…”

“…Cellular Automata Dual DraInagE Simulation modelling across a regular grid with parameters describing water input, output, and runoff speed at a cell‐by‐cell resolution (Webber, Fu, & Butler, )…”

“…Interventions were represented through spatial and temporal manipulation of cell roughness, input, and output parameters (Figure , Webber et al , b, c). Interventions which alter surface roughness are represented in CADDIES via Manning's “n” coefficient to control flow speed across a cell.…”

“…Costs of property damage have been calculated using a GIS‐based flood damage tool (Chen, Hammond, & Djordjevic, ). The tool operates through applying a function that attributes a damage cost for each cell based on the peak flood depth within it (Webber, Fu, & Butler, ). CADDIES is used to calculate peak flood depth maps, which alongside flood depth‐damage curves provide the basis for the calculation.…”

“…Availability, resolution, and quality of data are likely to vary on a country‐by‐country basis. Previous application of this framework has been limited to large‐scale analysis of strategic interventions, applied in blocks across a catchment (Webber, Fu, & Butler, ).…”